Development of an Integrated Intervention Plan

to Reduce Exposure to Lead and Other Contaminants in the Mining Center of

La Oroya, Perú

Prepared for

United States Agency for International Development, Peru Mission

By

Centers for Disease Control and Prevention National Center for Environmental Health/

Agency for Toxic Substances and Disease Registry Division of Emergency and Environmental Health

Services

May 2005

Development of an Integrated Intervention Plan to Reduce Exposure to Lead and Other Contaminants in the Mining Center of La Oroya, Peru U.S. Department of Health and Human Services Centers for Disease Control and Prevention National Center for Environmental Health Agency for Toxic Substances and Disease Registry Division of Emergency and Environmental Health Services Use of firm, trade, and brand names is for identification only and does not constitute endorsement by the U.S. Government Additional information can be obtained from Mr. Brian Hubbard, MPH Public Health Scientist CDC/NCEH/DEEH/EHSB 4770 Buford HWY, NE Mail stop: F-28 Atlanta, GA 30341 USA Telephone: 770.488.7098 Fax: 770.488.7310 E-mail: bnh5@cdc.gov Copies of this report are available in PDF format, which can be viewed using Adobe Acrobat Reader, at http://www.cdc.gov/nceh/ehs/Docs/la_oroya_report.pdf

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TABLE OF CONTENTS

Page

APPENDICES ................................................................................................................... 4

FIGURES........................................................................................................................... 4

TABLES ............................................................................................................................. 5

ABBREVATIONS.............................................................................................................. 5

ACKNOWLEDGEMENTS................................................................................................ 7

INVESTIGATORS AND COLLABORATORS: CDC ASSESSMENT TEAM............... 9

EXECUTIVE SUMMARY............................................................................................... 11

I. BACKGROUND ........................................................................................................... 13

A. The Mining Center of La Oroya, Peru .................................................................... 13

B. Purpose and Scope of the Assessment...................................................................... 15

II. CDC ASSESSMENT ACTIVITIES............................................................................ 16

III. FINDINGS FROM ASSESSMENT VISIT AND MEETINGS............................... 17

A. Child Blood Lead Level Studies in La Oroya ......................................................... 17

B. Environmental Contamination................................................................................. 19

C. Coordination of Activities ......................................................................................... 20

D. Hygiene ....................................................................................................................... 21

E. Communication.......................................................................................................... 21

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IV. DISCUSSION ............................................................................................................ 23

A. Importance of Lead ................................................................................................... 23

B. Lead and Human Health........................................................................................... 24

C. Global Lead Reduction Studies ................................................................................ 27

V. CONCLUSIONS.......................................................................................................... 33

VI. RECOMMENDATIONS ........................................................................................... 35

VII. REFERENCES ........................................................................................................ 37

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APPENDICES

Appendix A: USAID Technical Assistance Request

Appendix B: DIGESA Terms of Reference

Appendix C: CDC/NCEH Response to USAID Technical Assistance Request

Appendix D: Literature Review Including Spanish Language Publications

Appendix E: Information Resources Identified Through the Literature Review

Appendix F: Work Agenda for the CDC Technical Assistance Team–La Oroya

Site Visit

Appendix G: Preliminary Observations and Recommendations to Peruvian

Stakeholders, March 22, 2004

Appendix H: Three Case Studies

Appendix I: Chelation

Appendix J: Plan Development Framework

Appendix K: Problems/Issues/Concerns Clearly Stated

Appendix L: Problem Statement Worksheets

FIGURES

Figure 1. Pathways of lead from the environment to humans

Figure 2. Blood lead levels associated with adverse health effects

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Figure 3. Percentage of blood lead levels (BLLs) ≥10 µg/dL, by distance from the Met-

Mex Peñoles metal processing plant, Torreón, Coahuila, Mexico, 2003

Figure 4. Percent of children with elevated BLL (>10 ug/dL) by distance of residence

from Smelter in children less than 72 months of age

TABLES

Table 1. Blood lead levels, by distance from ASARCO smelter, El Paso, TX, August

1972

Table 2. Distribution of blood lead levels in children living in different sectors of the

Anapra Neighborhood, Ciudad de Juarez, Mexico, 1997

ABBREVIATIONS

ASARCO: American Smelting and Refining Company

ATSDR: Agency for Toxic Substances and Disease Registry

BLL: blood lead level

CDC: Centers for Disease Control and Prevention

DIGESA: Peruvian General Directorate of Environmental Health

INEI: National Institute for Informatics and Statistics

MEM: Ministry of Energy and Mines

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NCEH: National Center for Environmental Health

NGO: nongovernmental organization

NIOSH: National Institute for Occupational Safety and Health, CDC

µg/g: micrograms per gram

µg/dL: micrograms per deciliter

UNES: The Union for Sustainable Development Consortium

USAID: United States Agency for International Development

USEPA: United States Environmental Protection Agency

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ACKNOWLEDGEMENTS

The CDC Technical Assistance Team extends a special thank you to Eusebio Robles,

Juana Sueldo Mesones, and Rocio Espinoza Laín for project guidance and assistance in

facilitating the site visit.

The CDC Technical Assistance Team acknowledges the following institutions and

individuals for their work in understanding and resolving the complex environmental and

public health issues in La Oroya.

United States Agency for International

Development

Edilberto Alarcon

Timothy Miller

Marilu Bacigalupo

Martha Garcia

Peruvian Directorate of Environmental

Health

Juana Sueldo Mesones

Rocio Espinoza Laín

Eusebio Robles

Jorge Albinagorta

Department of Junín

Manual Duarte

Municipality of La Oroya

Clemente Quincho

Regional Environmental Council of the

Central Andean National Environmental

Commission

Carlos Rojas

Health Directorate Junín

Luis Huamani Palomino

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Ministry of Energy and Mines

César Polo Roosillard

Julio Bonelli Arenas

Maria Chappuis

Peruvian Ministry of Health

Juan de Dios Altamirano Del Pozo

Environmental Law Alliance Worldwide

Mercedes Lu

Interamerican Association for

Environmental Defense

Anna Cederstav

Consultant

Carmen Gastañaga

CARE Perú

Virginia Baffigo De Pinillos

Movement for the Health of La Oroya

Juan Aste

Eliana Ames

Occupational Knowledge International

Perry Gottesfeld

Doe Run Perú

José A. Mogrovejo

Juan Carlos Huyhua

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INVESTIGATORS AND COLLABORATORS: CDC ASSESSMENT TEAM

Sharunda Buchanan, Ph.D., Team Leader, Environmental Health Services Branch

Chief—Provides leadership direction and supervision to sanitarians, environmental

health service officers, epidemiologists, medical officers, and veterinarians involved in a

variety of environmental health services related-activities (i.e., sanitation, food

inspections and evaluations, air quality monitoring, waste water management, vector

control, etc.). Sdb4@cdc.gov

Pamela Meyer, Ph.D., Lead Health Scientist in the Lead Poisoning Prevention

Branch—Coordinates and oversees team of scientists working to enhance surveillance

for childhood lead poisoning and developing and evaluating interventions to prevent

children from becoming lead poisoned. Pfm7@cdc.gov

Oscar Tarrago, M.D., M.P.H., Health Risk Communication Leader, Division of

Health Education and Promotion—Develops environmental health training programs

for health personnel and coordinates trainings in health risk communication.

Oat3@cdc.gov

Gary Noonan, M.P.A., Director of Global Health Activities for the Division of

Environmental Hazards and Health Effects, Associate Director for Chemical

Terrorism—Coordinates the National Center for Environmental Health’s response in the

possible event of terrorist attack. Gpn2@cdc.gov

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John Sarisky, M.P.H., R.S., Senior Environmental Health Officer, Environmental

Health Services Branch—Responds to requests for technical assistance on

environmental public health issues from international, federal, state, and local agencies.

Has worked on environmental health projects in Peru for the past 4 years. Zse1@cdc.gov

Brian Hubbard, M.P.H., Environmental Health Scientist, Environmental Health

Services Branch—Provides technical assistance to international, national, state, and

local agencies to design and conduct environmental public health assessments and to

evaluate environmental public health programs. Has lived and worked in Peru for the past

4 years. Bnh5@cdc.gov

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EXECUTIVE SUMMARY

La Oroya, Peru, is home to a metal smelter that has operated for more than 80

years. In October 2003, the United States Agency for International Development

(USAID) asked the Centers for Disease Control and Prevention (CDC) to provide

technical assistance in the development of an integrated plan for addressing the

lead pollution problems in La Oroya. A team of scientists from CDC’s National

Center for Environmental Health (NCEH) visited Peru during March 13–22,

2004, to learn about the conditions and concerns in La Oroya. While in Peru, the

NCEH team visited the Doe Run Peru La Oroya smelter facility and discussed

smelter-related environmental public health issues with national, regional, and

local government officials; the smelter operator; health-care providers; concerned

citizens; and other stakeholders. The NCEH team also learned about the existing

environmental public health infrastructure and government oversight of the

mining industry in Peru. This report summarizes observations from meetings,

highlights relevant findings from studies conducted in various parts of the world,

and offers recommendations.

The situation in La Oroya is not a new environmental public health issue. Lead

has become an increasingly important problem in Latin American and the

Caribbean as a result of rapid industrialization. Studies conducted during the past

30 years in communities with metal processing plants throughout the world have

documented the relations between blood lead levels (BLLs) and lead levels in air

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and soil. The effects of lead are well known and range from subtle learning and

behavior impairment to seizures, coma, and death.

Major findings:

• Recent (1999–2001) BLL surveys conducted in La Oroya found all children

sampled had elevated BLLs (ranging from 15 to 80 micrograms per deciliter

[µg/dL]). These results indicate that the children of La Oroya are being

exposed to lead in their living environment.

• Emission control had not been implemented at the lead processing plant in La

Oroya.

• The extent of soil contamination has not been determined, and a soil

remediation plan has not been developed for implementation.

• The environmental public health infrastructure needed to control plant

emissions and oversee soil remediation efforts is fragmented and lacks

resources.

Recommendations:

The most immediate priority is to reduce exposure to lead and other contaminants. This

is best accomplished by building the environmental public health infrastructure needed to

develop and implement a comprehensive and integrated intervention plan. Stakeholders

need to unite and collaborate systemically to reduce emissions, remediate soil

contamination, and operate a sustainable monitoring system. Specifically, the process

should

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1. Reduce air lead emissions, both stack and fugitive, to levels that protect children from

having BLLs ≥10 µg/dL. Until this is accomplished no other interventions will have a

great impact on lowering children's BLLs.

2. Implement interventions that have been demonstrated scientifically to reduce lead

exposure from historical soil contamination.

3. Develop a scientifically robust plan to monitor the impact of emission reduction

efforts.

To strengthen the overall process and plan, and to improve credibility and ensure that

monitoring and other needs of affected parties are met, stakeholders should participate in

reduction planning, implementation, and monitoring of lead and other contaminants.

The framework presented at the closeout meeting on March 22, 2004, in Lima, Peru, and

recommendations contained in this report can guide stakeholders tasked with developing

and implementing a comprehensive intervention plan.

I. BACKGROUND

A. The Mining Center of La Oroya, Peru

The City of La Oroya, located in the mineral-rich department of Junín in the central sierra

of Perú, is the largest and oldest smelting and refining center for lead, copper, and zinc in

the country. Production processes also exist for cadmium, silver, gold, and other metals.

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The La Oroya metallurgic complex has a history of mining activities spanning 80 years.

La Oroya lies along the central highway and the Central Railway, the highest railway in

the world. Both transportation routes wind upward from Lima, through the mountains,

before reaching La Oroya at 3,371 meters. The city is 180 km northeast of Lima and has

a population of approximately 35,000. (For additional site description information, see

the following documents: La Oroya No Espera [Cederstav 2003]; Situación Ambiental

del Aire, Aguas, y Suelos en La Provincia de Yauli–La Oroya [UNES 2002]; Estudio de

Dispersión de la Contaminación Atmosférica de la Ciudad de la Oroya [DIGESA 2001];

Estudio Socio-económico 2001, Distrito La Oroya [INEI 2001]).

Results from studies conducted in Lima/Callao in 1998 and 1999 indicated that mineral

concentration deposits located near homes and educational centers were the main sources

of lead contamination causing elevated BLLs in children. Fifty percent of the mineral

concentration deposits in Lima/Callao storage facilities originate from La Oroya. As a

result of the Lima/Callao study, the General Directorate of Environmental Health

(DIGESA) carried out BLL studies in selected populations in La Oroya in November

1999. Results revealed an average BLL of 33.6 µg/dL (n=346) for children 6 months to

10 years of age (Hernandez-Avila et al. 1999). More striking were results indicating that

99.1% of children examined had BLLs >10 µg/dL, the level targeted for elimination by

2010 in the United States. Given the elevated BLLs in the zone, DIGESA prioritized

development of an integrated plan to improve the health of La Oroya residents.

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B. Purpose and Scope of the Assessment

On October 31, 2003, the Centers for Disease Control and Prevention (CDC) received a

technical assistance request developed by the United States Agency for International

Development (USAID). A CDC/USAID Peru Mission interagency agreement established

in 2001 allows USAID to request technical assistance from CDC on environmental and

public health issues. Amendment 6 of the CDC/USAID interagency agreement Number

AAG-P-00-99-00006-00 establishes the mechanism for requesting technical assistance.

The request was accompanied by specific terms of reference, developed by DIGESA. The

objective of the terms of reference is to support DIGESA management working to resolve

health problems in the La Oroya population resulting from exposure to environmental

contaminants believed to be associated with current and historical lead smelter

operations. The technical assistance request specified the following activities:

• Send a CDC team to La Oroya, Peru, to assess conditions that may be

contributing to reported health complaints and elevated BLLs;

• Determine pollution levels;

• Determine and assess current and planned activities to address the concerns in

La Oroya by Ministry of Health officials, specifically DIGESA personnel

working with mining officials, the operator of the smelter, community

members, health-care providers, and nongovernmental organizations (NGOs);

• After the 10-day visit to Peru and in coordination with DIGESA, develop a

work plan to address smelter-related health issues in La Oroya. The work plan

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will include terms of reference for future CDC assistance and recommended

actions for the ministries, mining groups, and other stakeholders.

II. CDC ASSESSMENT ACTIVITIES

In response to the technical assistance request (Appendix A) and accompanying terms of

reference (Appendix B), the CDC’s National Center for Environmental Health (NCEH)

was assigned the task and prepared a response to USAID on December 16, 2003

(Appendix C). Dr. Sharunda Buchanan, Chief of the NCEH Environmental Health

Services Branch organized and led the technical assistance team that

(1) Conducted an extensive literature review of health and environmental studies in La

Oroya and other mining and mineral processing communities (Appendix D). The

literature review identified 188 English-language and 15 Spanish-language

documents pertinent to conditions in La Oroya. The literature review was delivered

to USAID officials in December 2004. Key elements of several significant studies

and notable findings are presented in the Discussion section of this report. Electronic

and paper copies of lead-related documents and reports developed by U.S.

government agencies were provided to DIGESA, Ministry of Energy and Mines

(MEM), and USAID representatives during the March 2004 site visit. The literature

review also identified the information resources listed in Appendix E.

(2) Collaborated with USAID Peru Mission, DIGESA, Doe Run Peru mining officials,

and NGOs to develop a site visit agenda (Appendix F). The CDC team did not

16

collect human specimens or environmental samples or develop, review, or

recommend an environmental sampling plan or any plans to collect and analyze

human specimens.

(3) Completed technical site visits March 13–22, 2004, and met with key stakeholders in

an effort to understand the complex environmental public health issues in La Oroya.

(4) Presented preliminary observations and recommendations for the development of an

integrated intervention plan to Peruvian stakeholders on March 22, 2004, DIGESA

Central Office, Lima, Peru (Appendix G).

(5) Developed this report as a guide for DIGESA and other stakeholders for the

Development of an Integrated Intervention Plan to Reduce Exposure to Lead and

Other Contaminants in the Mining Center of La Oroya, Peru.

III. FINDINGS FROM ASSESSMENT VISIT AND MEETINGS

A. Child Blood Lead Level Studies in La Oroya

During the site visit, findings from three previous studies of children’s BLLs in La Oroya

were presented to the CDC team. DIGESA surveyed BLLs of 139 children ages 3–10

years living in Old La Oroya in 1999. Old La Oroya is 650 meters from the main stack of

the smelter. The DIGESA study reported BLLs ranging from 14.7 to 79.9 µg/dL. Mean

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BLL was 43.5 µg/dL (DIGESA 1999). All children participating from Old La Oroya had

BLLs >10 µg/dL. DIGESA also collected blood samples from 162 children aged 4–9

years living in New La Oroya. New La Oroya is approximately 2,500 meters from the

main stack. BLLs ranged from 6.9 to 67 µg/dL, and mean BLL was 26.6 µg/dL. Forty-

five children ages 3–9 years were enrolled in the study from Santa Rosa de Sacco, which

is 8,100 meters from the main stack of the smelter. BLLs ranged from 14.6 to 52.5 µg/dL,

and the mean BLL was 28.7 µg/dL.

UNES also surveyed BLLs of 30 children, from birth to age 3 years in 1999. Children

were enrolled in the study from Old La Oroya and Santa Rosa de Sacco. BLLs ranged

from 15.8 µg/dL to 64.7 µg/dL, with a mean of 41.8 µg/dL (UNES 1999). BLLs in all

children surveyed were >10 µg/dL.

Doe Run Peru surveyed BLLs of 252 children from birth to age 3 years in 2000–2001.

Mean BLL was 26.1 µg/dL. (PERU 2002). Mean BLLs for specific locations in the La

Oroya area were 36.7 µg/dL in Old La Oroya, 27.1 µg/dL in Buenos Aries/Huaymanta,

and 22.8 µg/dL in Santa Rosa de Sacco. Doe Run Peru did not report BLL ranges for

children aged 0–3 years in the respective study areas.

Review of results from these three BLL studies in the La Oroya zone indicates that BLLs

are elevated in the population living near to the Doe Run smelter. BLLs in La Oroya are

consistent with those studies in Mexico, the United States, and other countries, which

demonstrate that BLLs increase as distance to smelting activities decreases (See three

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case studies in Appendix H). BLL studies provide evidence that the smelting facility in

La Oroya is the main source of lead contamination in the zone.

B. Environmental Contamination

At the time of the CDC site visit (March 2004), the responsible parties had not agreed on

plans to control air emissions, nor had remediation efforts needed to address historical

soil contamination been implemented. In addition, the extent of contamination in the area

and the magnitude of impact on surface and groundwater quality, air quality, vegetation,

agricultural and ecologic systems, and human health had not been fully assessed. The

geographic distribution of lead and other contaminants of concern does not appear to be

well understood. No efforts have been made to remediate historical contamination. More

information is necessary to develop an effective plan to remediate historical

contamination

Accumulated lead resulting from the long history of smeltering activities in La Oroya is

evident by numerous, large slag piles. The impact of slag waste storage practices on

human health has not been fully investigated. How storage practices continue to

contribute to the historical contamination in the zone is unclear. Additionally, the impact

on health from transportation of material associated with smelter operations (truck, train,

conveyor belt system) has not been adequately assessed.

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At the time of the CDC assessment visit, the wastewater stream emanating from the

smelter facility was untreated. The impact of the wastewater on drinking water supplies,

surface water and groundwater, the watershed ecosystem, and downstream activities is

not well understood.

C. Coordination of Activities

No one group appears to be responsible for or to manage assessment, monitoring, and

remediation activities. A comprehensive plan to evaluate the environmental impact of

environmental lead reduction interventions in the La Oroya zone does not exist.

Similarly, no long-term coordinated plan exists to monitor BLLs as remediation efforts

reduce human exposure to lead and other contaminants. Implementation activities, data

collection efforts, and monitoring plans often are fragmented among agencies,

incomplete, and not ongoing. These activities appear sometimes to be managed outside of

the responsible governmental agency, and may not focus on the most important priorities:

reduce emissions and remediate historical contamination. Data collection efforts are not

coordinated and may be redundant. No one group has taken responsibility for

coordinating, collecting, reviewing, and summarizing environmental and health data.

Monitoring plans and data collection have not been agreed to, and the results from

existing assessments and investigations do not appear to be consistently shared with

stakeholders. Whether laboratory capacity exists within DIGESA for monitoring

activities is not clear; lack of such capacity may limit efforts to develop effective

monitoring systems for BLLs and remediation efforts.

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D. Hygiene

A hygiene education program is being implemented in La Oroya. Some local officials

thought hand washing and house cleaning would protect children from lead poisoning.

However, studies conducted around the world have demonstrated that efforts focused

solely on hygiene and behavior change will not yield significant results until reduction of

emission levels and remediation of historical contamination are prioritized.

E. Communication

A health risk communication plan does not exist for the La Oroya zone, and no process is

in place to develop a plan for communicating risk. The La Oroya community, national

and local government officials, Doe Run Peru management, and health-care providers do

not appear to have reached consensus on potential health impacts from exposure to

smelter operations. Limited public health infrastructure at the national and local levels

may impede collection and generation of information needed to clearly and promptly

communicate health status to authorities, decision makers, Doe Run Peru, and community

residents.

Health-care providers in La Oroya and Huancayo appear to place more priority on

curative measures than preventive measures. Health authorities may not have sufficient

information about measures that can significantly prevent and control human exposure to

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lead and other contaminants from mining activities. Without the appropriate information

and participation in active programs health-care providers support curative care more

than preventive care. The specific issue of chelation was addressed during the CDC visit

to the Regional Health Directorate in Huancayo. CDC’s recommendations are located in

Appendix I.

Current and culturally appropriate procedures for assessing children’s behavior and

symptoms for signs of lead poisoning are not widely and consistently used in La Oroya.

Access to appropriately designed tools to measure the chronic behavioral changes

associated with lead intoxication may afford local health-care providers a clearer

understanding of the extent of human health and contamination problems in La Oroya, as

well as in other mining communities. All children with elevated BLLs—virtually the

entire childhood population—should be evaluated for developmental delay, speech and

reading difficulties, and cognitive development at school entry.

Local residents receive conflicting educational material on environmental contaminants,

health effects, and risk levels. Some community members also expressed concern that

they were not fully participating in discussions and decision-making regarding health

impacts from exposure to contaminants.

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IV. DISCUSSION

A. Importance of Lead

Lead is a toxic metal that occurs naturally in the environment. The production and use of

lead in industry and in consumer products has exposed people to lead. Because lead is a

basic element, it cannot be degraded or broken down into a less toxic substance.

Therefore, when lead is found near human settlements by either naturally occurring or

anthropogenic processes, it may threaten public health until removed. Effective

technology exists to control lead in the environment. The best way to minimize

introduction of lead into the environment from industrial activities is to control

emissions.

The lead industry plays an important role in the economy of La Oroya and Peru. The

growing economies of other Latin American and the Caribbean countries also benefit

from the collection, transportation, and processing of lead-containing ore (Romieu et al.

1997). Lead has been used for hundreds of years in industrial and manufacturing

processes, and it is found in many products used today. Lead production increases with

demand for this natural resource. The mining and processing of lead containing ore can

release harmful contaminants into the environment. Even at low concentrations, exposure

to lead can be detrimental to human health. The processing of lead ore also can emit other

metals of concern, such as arsenic and cadmium (Baghurst et al. 1992; Landrigan et al.

23

1975; McMichael et al. 1985; Roels et al. 1980; Diaz-Barriga et al. 1997; Benin et al.

1999).

B. Lead and Human Health

Lead is not a natural constituent of the human body. Lead may enter the body by

ingestion and inhalation. Exposure pathways include industrial emissions, auto emissions,

lead-based paint, ambient air, indoor and outdoor dust, and soil (Figure 1). In

communities where lead is processed, air emissions are a primary concern. Airborne lead

from smelter operations accumulates in soil. Lead particles can be resuspended by wind

and human activities. Particles <10 µg, and especially those <2.5 µg, can bypass the

body’s respiratory defense systems and enter the lung. Particles >10 µg can be deposited

on food, and in soil and water, and ingested. Young children who commonly engage in

hand-to-mouth activities are more likely than older children or adults to ingest lead

contained in soil. Studies conducted around smelters suggest that direct inhalation of

airborne lead is the principal route of lead absorption for adults (Roels et al. 1980; Yankel

et al. 1977). In children the common route of exposure is ingestion of lead contaminated

soil (Yankel et al. 1977) and dust (Roels et al. 1980).

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Figure 1. Pathways of Lead from the Environment to Humans, Main Organs of

Absorption and Retention, and Main Routes of Excretion. (Sources USEPA, 1986;

USEPA, 1996a)

25

The effects of lead are well known and range from subtle learning and behavior

impairment to seizures, coma, and death (Figure 2). Children are vulnerable to lead’s

adverse health effects. At very high blood lead concentrations (≥80 µg/dL in children),

lead can cause encephalopathy (brain damage), coma, or death. At levels <60 µg/dL

distinctive symptoms may not be evident; however, children still can experience long-

term adverse health effects. Studies have found low to moderate BLLs in children are

related to learning and behavior problems. Even BLLs <10 µg/dL have adverse health

effects in children. No safe level of lead is known. Because most children with elevated

BLLs do not have symptoms that would prompt their families to seek medical care for

them, lead poisoning has been called the “silent epidemic”.

In adults, high BLLs are related to hypertension and cardiovascular disease. Lead can be

carried from maternal to fetal circulation through the placenta and enter the growing fetal

brain. That exposure of the fetus to lead, even at maternal blood levels <10 µg/dL,

adversely affects fetal brain development. (For additional information about the health

effects of lead exposure see Appendix D).

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Figure 2. Blood lead levels associated with adverse health effects

Children Lead Concentration in Blood(µg/dL) Adults

150

100

50

40

30

20

10

Death

Note: = increased function and = decreased function.

Encephalopathy

EncephalopathyNephropathy

Frank AnemiaColic

Nephropathy

Frank Anemia

Male Reproductive Effects

Hemoglobin Synthesis andFemale Reproductive Effects

Nerve Conduction VelocityHemoglobin Synthesis

Vitamin D Metabolism

Nerve Conduction Velocity

Erythrocyte ProtoporphyrinVitamin D Metabolism(?)

Developmental ToxicityIQ, Hearing, Growth

Transplacental Transfer

Elevated Blood Pressure

Erythrocyte Protoporphyrin(men)Erythrocyte Protoporphyrin(women)

Children Lead Concentration in Blood(µg/dL) Adults

150

100

50

40

30

20

10

Death

Note: = increased function and = decreased function.

Encephalopathy

EncephalopathyNephropathy

Frank AnemiaColic

Nephropathy

Frank Anemia

Male Reproductive Effects

Hemoglobin Synthesis andFemale Reproductive Effects

Nerve Conduction VelocityHemoglobin Synthesis

Vitamin D Metabolism

Nerve Conduction Velocity

Erythrocyte ProtoporphyrinVitamin D Metabolism(?)

Developmental ToxicityIQ, Hearing, Growth

Transplacental Transfer

Elevated Blood Pressure

Erythrocyte Protoporphyrin(men)Erythrocyte Protoporphyrin(women)

Source: Adapted from case studies in Environmental Medicine: Lead Toxicity, 1990, ATSDR

C. Global Lead Reduction Studies

The following series of studies summarize activities to identify and reduce human

exposure to contaminants generated by mining and metal processing activities. The

interventions implemented to protect human health are similar. Responsible authorities in

27

each community focused on control of emissions, and remediation of historical

contamination. These essential interventions also should be implemented in La Oroya.

The CDC technical assistance team emphasized the importance of developing an

intervention plan that integrates these lead reduction and control measures during their

presentation of preliminary observations and recommendations to Peruvian stakeholders

on March 22, 2004, in Lima, Peru (Appendix G).

The following studies and others (Appendix D) clearly show uncontrolled air emissions

from smelting activities to be correlated with high BLLs in populations residing near

smelter operations. High lead levels have been measured in air, soil, and dust near

smelters, and lead levels are highest closest to smelters for soil (Landrigan et al. 1975;

Landrigan et al. 1976; Garcia-Vargas et al. 2001; Díaz-Barriga et al. 1997), air (Roberts

et al. 1974; Roels et al. 1980; Landrigan et al. 1975; Garcia-Vargas et al. 2001), and dust

(Landrigan et al. 1975; Benin et al. 1999; Vargas et al. 2001). Lead concentrations in air,

soil, and dust are highly correlated with each other (Roels et al. 1980).

Elevated BLLs in children are related to high levels of lead in soil (Yankel et al. 1977;

Brunekreef et al. 1981; Hertzman et al. 1991; Cook et al. 1993; Kimbrough et al. 1995;

Lanphear BP 1998, Mielke and Reagan 1998), and lead in air (Landrigan et al. 1976).

Consequently, children living closest to smelters have higher BLLs than children living

farther away (Yankel et al. 1977; Letourneau and Gagne 1992; Landrigan et al. 1975;

Roels et al. 1980; Hertzman et al. 1991; Gagne 1994; Kimbrough et al. 1995; Albalak et

al. 2003; Maynard et al. 2003).

28

Table 1. Blood lead levels (BLLs) by distance from ASARCO smelter, El Paso, Texas,

August 1972.

Distance from

smelter

Age range

(years)

Number tested Percentage with

BLL 40–59

µg/dL*

Percentage with

BLL>59 µg/dL

<1 mile 1–4 49 55% 14%

5–9 101 34% 11%

10–19 109 25% 6%

≥20 98 16% 0

1–3 miles 1–4 83 23% 4%

5–9 124 12% 0

10–19 292 3% 1%

≥20 513 3% 1%

*Concentration of lead in micrograms per unit whole blood in deciliters (µg/dL whole blood)

Source: Landrigan, et al. (1975). Epidemic lead absorption near an ore smelter. The role of particulate lead.

N Engl J Med 292:123–9.

When the principal pathway of lead exposure, air emissions, is controlled, BLLs

decrease. Soil then replaces air as the primary source of lead exposure. A significant

portion of the population can be exposed to soil lead at concentrations that may elevate

BLLs to >10.0 µg/dL, the CDC-recommended action level for children. Young children

can be exposed to lead in indoor dust, especially when they exhibit hand-to-mouth

activities. Higher lead concentrations in indoor dust result in elevated lead concentrations

29

in nearby soil (Kimbrough et al. 1995; Louekari et al. 2004) and higher BLLs among

children (Brunekreef et al. 1981; Hertzman et al. 1991; Kimbrough et al. 1995). Studies

conducted around smelters after closure (Diaz-Barriga et al. 1997) or after a reduction in

emissions (Morse et al. 1979) show lead-contaminated soil to be an important source of

lead exposure for young children. This demonstrates the persistence of lead in the

environment, even after the source of contamination is controlled or removed.

Table 2. Distribution of BLLs in children living in different sectors of the Anapra

Neighborhood, Ciudad de Juarez, Mexico, 1997.

Blood Lead Levels (µg/dL)

Sector

<10.0 10.0–15.0 >15.0

I (within 600

meters of

smelter; n=7)

57% 29% 14%

II (600–1200

meters from

smelter; n=19)

79% 16% 5%

III (1200–1800

meters from

smelter; n=18)

89% 6% 5%

Source: Diaz-Barriga, F., Bates A, Calderon J, Lugo A, Galvao L, Lara I, et al. (1997). The El Paso Smelter

20 years later: residual impact on Mexican children. Environ Res 74:11–16.

30

Figure 3. Percentage of blood lead levels (BLLs) ≥10 µg/dL by distance from the Met-

Mex Peñoles metal processing plant, Torreón, Coahuila, Mexico, 2003

0

10

20

30

40

50

Distance from smelter (meters)

0-1500 1501-3000 3001-4500 4501-6000 >6000

808. 56

8 08 . 5 6

Perc

ent B

LLs

≥10 µg

/dL

*Distance from the plant was defined as the distance from the mid-point of the cluster where the child lives to the metallurgical plant

p-value<0.0001

n=25

n=100

n=139

n=70 n=33

Source: Albalak, R, McElroy, R, et al. (2003). Blood lead levels and risk factors for lead poisoning among

children in a Mexican smelting community. Arch Environ Health 58:172–183.

The feasibility of reducing children’s lead absorption near smelting facilities is well

established. When smelters are closed, air lead levels (TACB 1992) and children’s BLLs

(Diaz-Barriga et al. 1997) decrease dramatically. However, effective technology exists

that can reduce dangerous lead emissions without closing smelters (Prpic-Majic et al.

31

1992, Hilts et al. 2003, Louekari et al. 2004). Controlling air emissions and remediation

of contaminated soils have proven to substantially reduce BLLs.

Soil remediation efforts lower lead concentrations in soil (Gagne 1994; Lanphear et al.

2003), dust (Lanphear et al. 2003) and children’s BLLs (Von Lindern et al. 2003;

Lanphear et al. 2003). Children who place contaminated fingers, thumbs, or objects in

their mouths can ingest soil and dust containing lead. This childhood behavior is an

important source of exposure and highlights the need to reduce lead emissions to the air

while simultaneously removing lead-contaminated soil and dust (Roels et al. 1980).

Removing lead-contaminated dust from the living environment is difficult, especially

when lead emissions continue and lead-contaminated soil remains around the home.

Smelter workers also may bring lead dust into the family living environment. Without

reduction of air emissions and remediation of soil, home hygiene and clean neighborhood

campaigns are of little value in decreasing elevated BLLs. An evaluation of a dust

reduction effort that consisted of High Efficiency Particulate Air (HEPA) vacuuming

once every 6 weeks for 1 year found no effect on children’s BLLs and is not

recommended as the main intervention strategy in a community with high smelter lead

emissions (Hilts et al. 1995). Lead in house dust was decreased when lead soil

remediation and air pollution controls were implemented (Von Lindern et al. 2003).

Public health education and hygiene efforts alone are of little benefit in reducing elevated

BLLs. Educational interventions may help reduce BLLs after implementation of major

32

source-control measures, such as control of fugitive emissions and construction of new

state-of-the-art smelters (Hilts et al. 1998) or smelter closure (Kimbrough et al. 1995) and

soil and dust remediation (Goulet et al. 1996).

V. CONCLUSIONS

1. Minimal lead control exists. The Ministry of Energy and Mines, Directorate of

Environmental Health, Ministry of Health, Regional Environmental Council of

the Central Andean National Environmental Commission, Doe Run Peru, and

NGOs recognize the need to reduce the release of lead and other contaminants

from the Doe Run Peru smelter in La Oroya. However, lead reduction

interventions have been delayed. No action has been taken to remediate lead-

contaminated soil. An independent government authority does not monitor the

effectiveness and impact of implemented interventions. The presence of lead in

soil, dust, water resources, and ambient air probably will continue to keep BLLs

elevated in people in and around La Oroya. Ongoing discussions delay the

protection young children need in La Oroya

2. Authorities for lead control are fragmented. A fragmented multiagency system

exists to monitor and manage the environmental public health risks associated

with lead smelter operations in La Oroya. Agencies act independently. DIGESA

staff report they do not have the resources or authority to address the issues in La

Oroya. Several organizations, including Doe Run Peru, have requested

33

establishment of a multisectoral work team with active participation by the

Municipality, Ministry of Health, Ministry of Energy and Mines, Ministry of

Transportation, and Centromín Peru and others to develop and implement a La

Oroya Environmental Health and Hygiene plan.

3. Many stakeholders feel unrepresented. Concerned members of the community

and critical stakeholders are not part of this team. Some community members

believe their opinions and concerns are not considered by Doe Run Peru

management or government decision-makers. Community members and

stakeholders do not have a safe and open forum to express concerns and offer

solutions.

4. No comprehensive list exists of lead health and environmental issues. A

comprehensive list of problems, issues, and concerns associated with the La

Oroya metallurgic complex does not exist. Scientific literature indicates that

multiple metals often coexist, and these and other waste products of the smelting

process can adversely affect health. Metals and contaminants likely to affect

health include arsenic, cadmium, particulate matter, sulfur dioxide, and zinc.

5. Environmental and health impacts have not been established. Baseline

environmental and human health measures and impacts have not been established

for the region. Wastewater management practices at the Doe Run La Oroya

smelter are not adequately monitored by an independent government authority.

34

The lack of information about the impacts of wastewater may make development

of a plan to manage wastewater ineffective.

VI. RECOMMENDATIONS

The most immediate priority is to reduce exposure to lead and other contaminants. This

is best accomplished by building the environmental public health infrastructure needed to

develop and implement a comprehensive and integrated intervention plan. (The detailed

framework of such a plan is outlined in Appendix J). Stakeholders must unite and work

together systematically to reduce emissions, remediate soil contamination, and operate a

sustainable monitoring system. Specifically, the process should address the following

areas:

1. Reduce air lead emissions, both stack and fugitive, to levels that protect children from

having BLLs ≥10 µg/dL. Until this is accomplished, no other interventions will have a

great impact on lowering children's BLLs.

2. Implement interventions demonstrated scientifically to reduce lead exposure from

historical soil contamination.

3. Develop a scientifically robust plan to monitor the impact of emission reduction

efforts.

To strengthen the overall process and plan, and to improve credibility and ensure that

monitoring and other needs of affected parties are met, stakeholders should participate in

35

reduction planning, implementation, and monitoring not only of lead, but also of other

contaminants as well.

36

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